Assessment of the phenolic content, mutagenicity and genotoxicity of ethanolic extracts of stem bark and leaves from Strychnos pseudoquina A. St.-hil

Abstract

Strychnos pseudoquina is a plant species whose stem bark is used as bitter tonic beverage. The phytochemical analysis, as well as quantification of phenolic constituents and antioxidant activity of ethanolic extracts from S. pseudoquina stem bark, and leaves were conducted. The extracts were tested for mutagenicity (Ames test) and DNA-damaging activity (Plasmid Cleavage test). Leaves recorded the largest amount of flavonoids. The performed high-performance liquid chromatography (HPLC) showed flavonoids such as isorhamnetin and strychnobiflavone (phytochemical markers of the investigated species) in stem barks, but not in leaves. The proanthocyanidin content and antioxidant activity were significantly higher in stem barks than in leaves. Stem bark and leaf extracts presented mutagenic activity against TA98 and TA100 strains with, and without, metabolic activation (S9). The Plasmid Cleavage test did not indicate DNA-damaging activity. Our results suggest that extracts deriving from S. pseudoquina should be used with extreme caution, mainly the stem bark extract, which is widely used in folk medicine.

Hepatoprotective Native Plants Documented in Brazilian Traditional Medicine Literature: Current Knowledge and Prospects

“…Although plants belonging to the Strychnos genus may produce highly toxic alkaloids, strychnine was not found in the stem bark of S. pseudoquina, but caution is required in its popular use due to the cytotoxic and mutagenic effects demonstrated for its extracts. [151] Further toxicological studies conducted by Silva et al [152] with the alcoholic and the alkaloid-enriched fraction from leaves of this species did not show mortality or liver toxic effects after its oral administration in mice (5 g/kg) for a period of 2 weeks.…”

“…The extracts were not able to prevent the hepatocellular injury after a 30‐day treatment, as revealed by biochemical and histopathological analysis, but presented a possible choleretic/cholagogue effect. Although plants belonging to the Strychnos genus may produce highly toxic alkaloids, strychnine was not found in the stem bark of S. pseudoquina , but caution is required in its popular use due to the cytotoxic and mutagenic effects demonstrated for its extracts [151] . Further toxicological studies conducted by Silva et al [152] .…”

Toxicity of Bioactive Compounds of Strychnos pseudoquina (Loganiaceae) in Spodoptera frugiperda (Noctuidae)

“…Phytochemical characteristics and pharmacological properties of S. pseudoquina have been relatively well studied [23][24][25][26][27][28][29], although the use of these plants is still primarily based on folk medicine, and, to date, there are no published studies reporting the insecticidal potential of Strychnos species.…”

Structural and Anticancer Studies of Methoxyflavone Derivative from Strychnos pseudoquina A.St.-Hil. (Loganiaceae) from Brazilian Cerrado

“…The Cerrado is the second largest biome in Brazil by area and the world’s richest savanna in terms of biodiversity. , Its high degree of endemism and the loss of its native area of approximately 46%, due to agricultural expansion processes, have made it one of the 34 hot spots for conservation in the world. , Among the species of native Cerrado plants, Strychnos pseudoquina stands out, popularly known as “quina-do-cerrado”. − Regarding phytochemical studies using S. pseudoquina, the presence of secondary metabolites such as alkaloids and flavonoids is normally demonstrated, and their occurrence is explained by soil conditions, frequent fires, and water stress existing in the Cerrado. ,− …”

“… 3 , 4 Among the species of native Cerrado plants, Strychnos pseudoquina stands out, popularly known as “quina-do-cerrado”. 5 − 7 Regarding phytochemical studies using S. pseudoquina , the presence of secondary metabolites such as alkaloids and flavonoids is normally demonstrated, and their occurrence is explained by soil conditions, frequent fires, and water stress existing in the Cerrado. 4 , 8 − 12 …”